首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   82872篇
  免费   7619篇
  国内免费   159篇
耳鼻咽喉   770篇
儿科学   2713篇
妇产科学   1834篇
基础医学   10868篇
口腔科学   1624篇
临床医学   11998篇
内科学   15448篇
皮肤病学   1088篇
神经病学   7286篇
特种医学   2602篇
外国民族医学   2篇
外科学   9471篇
综合类   1508篇
一般理论   75篇
预防医学   10679篇
眼科学   1241篇
药学   6075篇
中国医学   121篇
肿瘤学   5247篇
  2023年   451篇
  2022年   734篇
  2021年   1413篇
  2020年   946篇
  2019年   1558篇
  2018年   1807篇
  2017年   1319篇
  2016年   1427篇
  2015年   1632篇
  2014年   2240篇
  2013年   3425篇
  2012年   4979篇
  2011年   5160篇
  2010年   2801篇
  2009年   2617篇
  2008年   4637篇
  2007年   4744篇
  2006年   4647篇
  2005年   4525篇
  2004年   4182篇
  2003年   3816篇
  2002年   3693篇
  2001年   1767篇
  2000年   1664篇
  1999年   1725篇
  1998年   1010篇
  1997年   791篇
  1996年   722篇
  1995年   680篇
  1994年   634篇
  1993年   672篇
  1992年   1334篇
  1991年   1238篇
  1990年   1159篇
  1989年   1137篇
  1988年   1057篇
  1987年   1043篇
  1986年   1059篇
  1985年   977篇
  1984年   868篇
  1983年   709篇
  1982年   514篇
  1981年   445篇
  1980年   409篇
  1979年   627篇
  1978年   515篇
  1977年   407篇
  1976年   401篇
  1974年   448篇
  1973年   408篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
OBJECTIVES: Diagnostic accuracy of the ThinPrep process (Cytyc, Boxborough, MA) was compared with that of conventional (smear) cytopreparation for fine-needle aspiration (FNA) of head and neck masses. METHODS: In a prospective, randomized, single-blinded study, 209 patients served as their own controls and underwent 236 FNAs using ThinPrep and conventional (smear) cytopreparatory techniques. RESULTS: ThinPrep produced less air-drying artifact and less mechanical distortion than the conventional method. The conventional technique was diagnostic in 63% of samples; the ThinPrep technique was diagnostic in 55% of samples. When all results were combined, pathologists subjectively preferred the conventional technique but accepted use of ThinPrep as the only cytopreparatory technique for most head and neck masses. CONCLUSIONS: For adequately experienced cytopathologists, ThinPrep is acceptable for FNA of salivary masses, neck cysts, metastatic lymph nodes, and thyroid lesions. Conventional smear technique should be used for FNA of nonmetastatic lymphoid lesions. Use of ThinPrep can complement use of the conventional (smear) cytopreparatory technique when aspirate is nondiagnostic or bloody, when the patient has a blood-borne infectious disease, when the clinician is inexperienced, or when aspirate has entered the syringe.  相似文献   
52.
Endoscopic balloon dilatation was undertaken in seven patients who presented with obstructive symptoms resulting from Crohn's disease. Five patients had strictures from recurrent disease at the site of an ileotransverse anastomosis, one had duodenal stenosis and one a colonic stricture. The procedures were performed under intravenous sedation on one to four occasions (median 2) and were uncomplicated. Sustained improvement over an 18-24-month follow-up period was achieved in five patients, but dilatation was unsuccessful in two cases. Endoscopic balloon dilatation is a safe and effective option in selected patients with intestinal strictures resulting from Crohn's disease and may overcome the need for surgery.  相似文献   
53.
BACKGROUND: The long-term observation of vegetarians in affluent countries can provide insight into the relative effects of a vegetarian diet and lifestyle factors on mortality. METHODS: A cohort study of vegetarians and health-conscious persons in Germany was followed-up prospectively for 21 years, including 1,225 vegetarians and 679 health-conscious nonvegetarians. Standardized mortality ratios compared with the German general population were calculated for all causes and specific causes. Within the cohort, Poisson regression modeling was used to investigate the joint effects of several risk factors on overall and cause-specific mortality. RESULTS: Standardized mortality ratios for all-cause mortality was significantly below 100: 59 [95% confidence interval (95% CI), 54-64], predominantly due to a deficit of deaths from circulatory diseases. Within the cohort, vegetarian compared with nonvegetarian diet had no effect on overall mortality [rate ratio (RR), 1.10; 95% CI, 0.89-1.36], whereas moderate and high physical activity significantly reduced risk of death (RR, 0.62, 0.64), adjusted for age, sex, smoking, alcohol intake, body mass index, and educational level. Vegetarian diet was however associated with a reduced RR of 0.70 (95% CI, 0.41-1.18) for ischemic heart disease, which could partly be related to avoidance of meat. CONCLUSIONS: Both vegetarians and nonvegetarian health-conscious persons in this study have reduced mortality compared with the general population. Within the study, low prevalence of smoking and moderate or high level of physical activity but not strictly vegetarian diet was associated with reduced overall mortality. The nonsignificant reduction in mortality from ischemic heart diseases in vegetarians compared with health-conscious persons could be explained in part by avoidance of meat intake.  相似文献   
54.
55.
56.
57.
The literature suggests that pain in the elderly, especially among seniors with dementia, is under-assessed and under-treated.This qualitative study solicited the perspectives of seniors, front-line nursing staff, nursing-home administrators, and informal caregivers of seniors with dementia on the current status of pain assessment and management. The views of these participants complement the research findings reported in the literature. While some of their explanations and potential solutions concerning under-treatment of pain in seniors echo views that have been presented in the literature, the participants also pointed to factors and avenues that have been given less formal consideration (e.g., systemic barriers to effective assessment and treatment of pain).They also highlighted the need for pain-control strategies beyond medication. The implications of these findings are discussed.  相似文献   
58.
A convenience sample of hospital workers, those receiving influenza vaccine and those not receiving vaccine, were asked to complete questionnaires delineating the occurrence of symptoms (e.g., fever, headache, extreme tiredness, dry cough, sore throat, runny nose, stuffy nose, muscle aches) and absenteeism in the 7-day period post-vaccination if vaccinated. Those unvaccinated completed the questionnaire in a self-selected 7 consecutive day period during the study conducted from November 2004 to February 2005. Those receiving either Fluzone or FluMist reported significantly fewer symptoms and related absenteeism than the unvaccinated group (p < .05). Administration of influenza vaccine did not result in higher rates of post-vaccination symptoms as compared to an unvaccinated group. Further, vaccinated employees did not experience higher absenteeism rates as a result of receiving either influenza vaccine. However, for those reporting absenteeism as a result of symptoms, mean absenteeism days were highest in the FluMist group (4.5 days) compared to the unvaccinated group (2.1 days) and the Fluzone group (1.9 days).  相似文献   
59.
60.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号